Cachexia is a condition characterized by weight loss, muscle atrophy, anorexia, fatigue, and weakness. It is commonly seen in patients with chronic progressive diseases such as AIDS, hormone deficiency, chronic obstructive lung disease (COPD), congestive heart failure (CHF), tuberculosis (TB), and cancer. In cachexia, a decline in food intake relative to energy expenditure leads to weight loss. Even with adequate nutritional support, abnormalities in the metabolism of carbohydrates, proteins, and fats causes continued mobilization and ineffective repletion of host tissue. The physiological mechanisms that cause cachexia remain poorly understood, although cachectin/TNF or other inflammatory cytokines have been implicated.
Nutritional support can help maintain the body weight of cachectic patients, but does not prevent loss of lean muscle mass. Steroids (particularly progesterone-like drugs) can increase appetite and reverse weight loss, although again there is no evidence that it reverses the loss of muscle mass. A humanized anti-IL-6 antibody was evaluated as a treatment for cachexia in a clinical trial involving lung cancer patients. The antibody appeared to be safe and well tolerated, improved the lung symptom score, reversed fatigue, and reduced the rate of lean body mass loss. It did not, however, reverse this process.